Filter for printhead assembly

ABSTRACT

A method of supplying liquid ink to a printhead assembly including a carrier, a printhead die mounted on the carrier, and a fluid delivery assembly communicated with the carrier includes communicating a fluid manifold of the carrier with the printhead die, communicating the fluid delivery assembly with the fluid manifold of the carrier, and filling the fluid delivery assembly with a quantity of the liquid ink, including purging air from the fluid delivery assembly through a filter, wherein the filter includes a frame having an opening and a fluid passage communicated with the opening formed therein, filter material enclosing the opening and the fluid passage of the frame, first and second fluid ports communicated with the fluid passage, and a permeable material communicated with the first fluid port.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of copending U.S. patent applicationSer. No. 10/635,409, filed on Aug. 6, 2003, which is related to U.S.patent application Ser. No. 10/635,636, filed on Aug. 6, 2003, both ofwhich are assigned to the assignee of the present invention, andincorporated herein by reference.

BACKGROUND

A conventional inkjet printing system includes a printhead, an inksupply which supplies liquid ink to the printhead, and an electroniccontroller which controls the printhead. The printhead ejects ink dropsthrough a plurality of orifices or nozzles and toward a print medium,such as a sheet of paper, so as to print onto the print medium.Typically, the nozzles are arranged in one or more arrays such thatproperly sequenced ejection of ink from the nozzles causes characters orother images to be printed upon the print medium as the printhead andthe print medium are moved relative to each other.

In one arrangement, commonly referred to as a wide-array inkjet printingsystem, a plurality of individual printheads, also referred to asprinthead dies, are mounted on a single carrier. As such, a number ofnozzles and, therefore, an overall number of ink drops which can beejected per second is increased. Since the overall number of ink dropswhich can be ejected per second is increased, printing speed can beincreased with the wide-array inkjet printing system.

During filling and/or operation of the printhead, air may accumulatewithin the printhead. For example, as the printhead is filled withliquid ink, displaced air will exist. In addition, with differentorientations of the printhead, the internal geometry of the printheadmay create dead zones within the printhead where air can become trapped.Unfortunately, the accumulation of air within the printhead mayadversely effect operation of the printhead.

For these and other reasons, there is a need for the present invention.

SUMMARY

One aspect of the present invention provides a method of supplyingliquid ink to a printhead assembly including a carrier, a printhead diemounted on the carrier, and a fluid delivery assembly communicated withthe carrier. The method includes communicating a fluid manifold of thecarrier with the printhead die, communicating the fluid deliveryassembly with the fluid manifold of the carrier, and filling the fluiddelivery assembly with a quantity of the liquid ink, including purgingair from the fluid delivery assembly through a filter, wherein thefilter includes a frame having an opening and a fluid passagecommunicated with the opening formed therein, filter material enclosingthe opening and the fluid passage of the frame, first and second fluidports communicated with the fluid passage, and a permeable materialcommunicated with the first fluid port.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating one embodiment of an inkjetprinting system.

FIG. 2 is a top perspective view illustrating one embodiment of aprinthead assembly.

FIG. 3 is a bottom perspective view of the printhead assembly of FIG. 2.

FIG. 4 is a schematic cross-sectional view illustrating portions of oneembodiment of a printhead die.

FIG. 5 is a schematic cross-sectional view illustrating one embodimentof a printhead assembly.

FIG. 6 is a schematic cross-sectional view illustrating one embodimentof a portion of a substrate for a printhead assembly.

FIG. 7 is an exploded top perspective view illustrating one embodimentof a carrier for a printhead assembly.

FIG. 8 is a bottom perspective view of the carrier of FIG. 7.

FIG. 9 is a top perspective view illustrating one embodiment of a fluiddelivery assembly for a printhead assembly.

FIG. 10 is a schematic illustration of one embodiment of a fluiddelivery assembly and a carrier for a printhead assembly.

FIG. 11 is an exploded perspective view illustrating one embodiment of afilter for a printhead assembly.

FIG. 12 is a perspective view illustrating another embodiment of aportion of a filter for a printhead assembly.

FIGS. 13A and 13B are schematic cross-sectional views of one embodimentof a printhead assembly oriented for filling of the printhead assemblywith liquid ink.

FIG. 14 is a schematic cross-sectional view of one embodiment of aprinthead assembly oriented for operation of the printhead assembly andincluding one embodiment of a filter for the printhead assembly.

FIG. 15 is a schematic cross-sectional view of one embodiment of aprinthead assembly oriented for operation of the printhead assembly andincluding another embodiment of a filter for the printhead assembly.

FIGS. 16A and 16B are schematic cross-sectional views of the printheadassembly of FIG. 15 oriented at negative and positive angles relative toa vertical orientation.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which is shown byway of illustration specific embodiments in which the invention may bepracticed. In this regard, directional terminology, such as “top,”“bottom,” “front,” “back,” “leading,” “trailing,” etc., is used withreference to the orientation of the Figure(s) being described. Becausecomponents of embodiments of the present invention can be positioned ina number of different orientations, the directional terminology is usedfor purposes of illustration and is in no way limiting. It is to beunderstood that other embodiments may be utilized and structural orlogical changes may be made without departing from the scope of thepresent invention. The following detailed description, therefore, is notto be taken in a limiting sense, and the scope of the present inventionis defined by the appended claims.

FIG. 1 illustrates one embodiment of an inkjet printing system 10.Inkjet printing system 10 includes a printhead assembly 12, an inksupply assembly 14, a mounting assembly 16, a media transport assembly18, and an electronic controller 20. Printhead assembly 12 is formedaccording to an embodiment of the present invention, and includes one ormore printheads which eject drops of ink or fluid through a plurality oforifices or nozzles 13.

In one embodiment, the drops of ink are directed toward a medium, suchas print medium 19, so as to print onto print medium 19. Print medium 19includes any type of suitable sheet material, such as paper, card stock,transparencies, Mylar, and the like. Typically, nozzles 13 are arrangedin one or more columns or arrays such that properly sequenced ejectionof ink from nozzles 13 causes, in one embodiment, characters, symbols,and/or other graphics or images to be printed upon print medium 19 asprinthead assembly 12 and print medium 19 are moved relative to eachother.

Ink supply assembly 14 supplies ink to printhead assembly 12 andincludes a reservoir 15 for storing ink. As such, in one embodiment, inkflows from reservoir 15 to printhead assembly 12. In one embodiment,printhead assembly 12 and ink supply assembly 14 are housed together inan inkjet cartridge or pen. In another embodiment, ink supply assembly14 is separate from printhead assembly 12 and supplies ink to printheadassembly 12 through an interface connection, such as a supply tube.

Mounting assembly 16 positions printhead assembly 12 relative to mediatransport assembly 18 and media transport assembly 18 positions printmedium 19 relative to printhead assembly 12. Thus, a print zone 17 isdefined adjacent to nozzles 13 in an area between printhead assembly 12and print medium 19. In one embodiment, printhead assembly 12 is ascanning type printhead assembly and mounting assembly 16 includes acarriage for moving printhead assembly 12 relative to media transportassembly 18. In another embodiment, printhead assembly 12 is anon-scanning type printhead assembly and mounting assembly 16 fixesprinthead assembly 12 at a prescribed position relative to mediatransport assembly 18.

Electronic controller 20 communicates with printhead assembly 12,mounting assembly 16, and media transport assembly 18. Electroniccontroller 20 receives data 21 from a host system, such as a computer,and includes memory for temporarily storing data 21. Typically, data 21is sent to inkjet printing system 10 along an electronic, infrared,optical or other information transfer path. Data 21 represents, forexample, a document and/or file to be printed. As such, data 21 forms aprint job for inkjet printing system 10 and includes one or more printjob commands and/or command perimeters.

In one embodiment, electronic controller 20 provides control ofprinthead assembly 12 including timing control for ejection of ink dropsfrom nozzles 13. As such, electronic controller 20 defines a pattern ofejected ink drops which form characters, symbols, and/or other graphicsor images on print medium 19. Timing control and, therefore, the patternof ejected ink drops is determined by the print job commands and/orcommand perimeters. In one embodiment, logic and drive circuitry forminga portion of electronic controller 20 is located on printhead assembly12. In another embodiment, logic and drive circuitry is located offprinthead assembly 12.

FIGS. 2 and 3 illustrate one embodiment of a portion of printheadassembly 12. Printhead assembly 12 is a wide-array or multi-headprinthead assembly and includes a carrier 30, a plurality of printheaddies 40, an ink or fluid delivery system 50, and an electronic interfacesystem 60. Carrier 30 has an exposed surface or first face 301 and anexposed surface or second face 302 which is opposite of and orientedsubstantially parallel with first face 301. Carrier 30 serves to carryor provide mechanical support for printhead dies 40. In addition,carrier 30 accommodates fluidic communication between ink supplyassembly 14 and printhead dies 40 via ink delivery system 50 andaccommodates electrical communication between electronic controller 20and printhead dies 40 via electronic interface system 60.

Printhead dies 40 are mounted on first face 301 of carrier 30 andaligned in one or more rows. In one embodiment, printhead dies 40 arespaced apart and staggered such that printhead dies 40 in one rowoverlap at least one printhead die 40 in another row. Thus, printheadassembly 12 may span a nominal page width or a width shorter or longerthan nominal page width. While four printhead dies 40 are illustrated asbeing mounted on carrier 30, the number of printhead dies 40 mounted oncarrier 30 may vary.

In one embodiment, a plurality of inkjet printhead assemblies 12 aremounted in an end-to-end manner. In one embodiment, to provide for atleast one printhead die 40 of one printhead assembly 12 overlapping atleast one printhead die 40 of an adjacent printhead assembly 12, carrier30 has a staggered or stair-step profile. While carrier 30 isillustrated as having a stair-step profile, it is within the scope ofthe present invention for carrier 30 to have other profiles including asubstantially rectangular profile.

Ink delivery system 50 fluidically couples ink supply assembly 14 withprinthead dies 40. In one embodiment, ink delivery system 50 includes afluid manifold 52 and a fluid port 54. Fluid manifold 52 is formed incarrier 30 and distributes ink through carrier 30 to each printhead die40. Fluid port 54 communicates with fluid manifold 52 and provides aninlet for ink supplied by ink supply assembly 14.

Electronic interface system 60 electrically couples electroniccontroller 20 with printhead dies 40. In one embodiment, electronicinterface system 60 includes a plurality of electrical contacts 62 whichform input/output (I/O) contacts for electronic interface system 60. Assuch, electrical contacts 62 provide points for communicating electricalsignals between electronic controller 20 and printhead assembly 12.Examples of electrical contacts 62 include I/O pins which engagecorresponding I/O receptacles electrically coupled to electroniccontroller 20 and I/O contact pads or fingers which mechanically orinductively contact corresponding electrical nodes electrically coupledto electronic controller 20. Although electrical contacts 62 areillustrated as being provided on second face 302 of carrier 30, it iswithin the scope of the present invention for electrical contacts 62 tobe provided on other sides of carrier 30.

As illustrated in the embodiments of FIGS. 2 and 4, each printhead die40 includes an array of drop ejecting elements 42. Drop ejectingelements 42 are formed on a substrate 44 which has an ink or fluid feedslot 441 formed therein. As such, fluid feed slot 441 provides a supplyof ink or fluid to drop ejecting elements 42. Substrate 44 is formed,for example, of silicon, glass, or a stable polymer.

In one embodiment, each drop ejecting element 42 includes a thin-filmstructure 46 and an orifice layer 47. Thin-film structure 46 includes afiring resistor 48 and has an ink or fluid feed channel 461 formedtherein which communicates with fluid feed slot 441 of substrate 44.Orifice layer 47 has a front face 471 and a nozzle opening 472 formed infront face 471. Orifice layer 47 also has a nozzle chamber 473 formedtherein which communicates with nozzle opening 472 and fluid feedchannel 461 of thin-film structure 46. Firing resistor 48 is positionedwithin nozzle chamber 473 and includes leads 481 which electricallycouple firing resistor 48 to a drive signal and ground.

Thin-film structure 46 is formed, for example, by one or morepassivation or insulation layers of silicon dioxide, silicon carbide,silicon nitride, tantalum, poly-silicon glass, or other suitablematerial. In one embodiment, thin-film structure 46 also includes aconductive layer which defines firing resistor 48 and leads 481. Theconductive layer is formed, for example, by aluminum, gold, tantalum,tantalum-aluminum, or other metal or metal alloy.

In one embodiment, during operation, ink or fluid flows from fluid feedslot 441 to nozzle chamber 473 via fluid feed channel 461. Nozzleopening 472 is operatively associated with firing resistor 48 such thatdroplets of ink or fluid are ejected from nozzle chamber 473 throughnozzle opening 472 (e.g., normal to the plane of firing resistor 48) andtoward a medium upon energization of firing resistor 48.

Example embodiments of printhead dies 40 include a thermal printhead, asdescribed above, a piezoelectric printhead, a flex-tensional printhead,or any other type of fluid ejection device known in the art. In oneembodiment, printhead dies 40 are fully integrated thermal inkjetprintheads.

Referring to the embodiments of FIGS. 2, 3, and 5, carrier 30 includes asubstrate 32 and a substructure 34. Substrate 32 and substructure 34provide and/or accommodate mechanical, electrical, and fluidic functionsof printhead assembly 12. More specifically, substrate 32 providesmechanical support for printhead dies 40, accommodates fluidiccommunication between ink supply assembly 14 and printhead dies 40 viaink delivery system 50, and provides electrical connection between andamong printhead dies 40 and electronic controller 20 via electronicinterface system 60. Substructure 34 provides mechanical support forsubstrate 32, accommodates fluidic communication between ink supplyassembly 14 and printhead dies 40 via ink delivery system 50, andaccommodates electrical connection between printhead dies 40 andelectronic controller 20 via electronic interface system 60.

Substrate 32 has a first side 321 and a second side 322 which isopposite first side 321, and substructure 34 has a first side 341 and asecond side 342 which is opposite first side 341. In one embodiment,printhead dies 40 are mounted on first side 321 of substrate 32 andsubstructure 34 is disposed on second side 322 of substrate 32. As such,first side 341 of substructure 34 contacts and is joined to second side322 of substrate 32.

For transferring ink between ink supply assembly 14 and printhead dies40, substrate 32 and substructure 34 each have a plurality of ink orfluid passages 323 and 343, respectively, formed therein. Fluid passages323 extend through substrate 32 and provide a through-channel orthrough-opening for delivery of ink to printhead dies 40 and, morespecifically, fluid feed slot 441 of substrate 44 (FIG. 4). Fluidpassages 343 extend through substructure 34 and provide athrough-channel or through-opening for delivery of ink to fluid passages323 of substrate 32. As such, fluid passages 323 and 343 form a portionof ink delivery system 50. Although only one fluid passage 323 is shownfor a given printhead die 40, there may be additional fluid passages tothe same printhead die, for example, to provide ink of respectivediffering colors.

For transferring electrical signals between electronic controller 20 andprinthead dies 40, electronic interface system 60 includes a pluralityof conductive paths 64 extending through substrate 32, as illustrated inFIG. 6. More specifically, substrate 32 includes conductive paths 64which pass through and terminate at exposed surfaces of substrate 32. Inone embodiment, conductive paths 64 include electrical contact pads 66at terminal ends thereof which form, for example, I/O bond pads onsubstrate 32. Conductive paths 64, therefore, terminate at and provideelectrical coupling between electrical contact pads 66.

Electrical contact pads 66 provide points for electrical connection tosubstrate 32 and, more specifically, conductive paths 64. Electricalconnection is established, for example, via electrical connectors orcontacts 62, such as I/O pins or spring fingers, wire bonds, electricalnodes, and/or other suitable electrical connectors. In one embodiment,printhead dies 40 include electrical contacts 41 which form I/O bondpads. As such, electronic interface system 60 includes electricalconnectors, for example, wire bond leads 68, which electrically coupleelectrical contact pads 66 with electrical contacts 41 of printhead dies40.

Conductive paths 64 transfer electrical signals between electroniccontroller 20 and printhead dies 40. More specifically, conductive paths64 define transfer paths for power, ground, and data among and/orbetween printhead dies 40 and electrical controller 20. In oneembodiment, data includes print data and non-print data.

In one embodiment, as illustrated in FIG. 6, substrate 32 includes aplurality of layers 33 each formed of a ceramic material. As such,substrate 32 includes circuit patterns which pierce layers 33 to formconductive paths 64. While substrate 32 is illustrated as includinglayers 33, it is, however, within the scope of the present invention forsubstrate 32 to be formed of a solid pressed ceramic material. As such,conductive paths are formed, for example, as thin-film metallized layerson the pressed ceramic material.

While conductive paths 64 are illustrated as terminating at first side321 and second side 322 of substrate 32, it is, however, within thescope of the present invention for conductive paths 64 to terminate atother sides of substrate 32. In addition, one or more conductive paths64 may branch from and/or lead to one or more other conductive paths 64.Furthermore, one or more conductive paths 64 may begin and/or end withinsubstrate 32. Conductive paths 64 may be formed as described, forexample, in U.S. Pat. No. 6,428,145, entitled “Wide-Array Printheadassembly with Internal Electrical Routing System” assigned to theassignee of the present invention.

It is to be understood that FIGS. 5 and 6 are simplified schematicillustrations of one embodiment of carrier 30, including substrate 32and substructure 34. The illustrative routing of fluid passages 323 and343 through substrate 32 and substructure 34, respectively, andconductive paths 64 through substrate 32, for example, has beensimplified for clarity of the invention. Although various features ofcarrier 30, such as fluid passages 323 and 343 and conductive paths 64,are schematically illustrated as being straight, it is understood thatdesign constraints could make the actual geometry more complicated for acommercial embodiment of printhead assembly 12. Fluid passages 323 and343, for example, may have more complicated geometries to allow multiplecolorants of ink to be channeled through carrier 30. In addition,conductive paths 64 may have more complicated routing geometries throughsubstrate 32 to avoid contact with fluid passages 323 and to allow forelectrical connector geometries other than the illustrated I/O pins. Itis understood that such alternatives are within the scope of the presentinvention.

FIGS. 7 and 8 illustrate one embodiment of carrier 30 includingsubstrate 32 and substructure 34. As described above, substrate 32includes a plurality of fluid passages 323. Printhead dies 40 aremounted on substrate 32 such that each printhead die 40 communicateswith one fluid passage 323. In addition, substructure 34 has fluidmanifold 52 defined therein and includes fluid port 54. As such,substrate 32 forms a first side of carrier 30 and substructure 34 formsa second side of carrier 30 opposite the first side thereof. Thus, fluidpassages 323 communicate with the first side of carrier 30 and fluidport 54 communicates with the second side of carrier 30. Substructure 34supports substrate 32 such that fluid from fluid port 54 is distributedto fluid passages 323 and printhead dies 40 through fluid manifold 52.

In one embodiment, as illustrated in FIG. 9, fluid delivery system 50includes a fluid delivery assembly 70. Fluid delivery assembly 70receives fluid from a fluid source and, in one embodiment, regulates apressure of the fluid and filters the fluid for delivery to carrier 30.Fluid delivery assembly 70 is coupled with carrier 30 so as tocommunicate, in one embodiment, pressure regulated and filtered fluidwith fluid manifold 52 of carrier 30.

In one embodiment, fluid delivery assembly 70 includes a housing 72, afluid inlet 74, and a fluid outlet 76. Fluid inlet 74 communicates witha supply of fluid such as reservoir 15 of ink supply assembly 14 (FIG.1). In one embodiment, fluid delivery assembly 70 includes a chamberwhich communicates with fluid inlet 74 and fluid outlet 76 such thatfluid received at fluid inlet 74 is supplied to fluid outlet 76. Fluidoutlet 76 communicates with fluid port 54 of carrier 30 such that fluidfrom fluid delivery assembly 70 is supplied to fluid manifold 52 ofcarrier 30.

Fluid outlet 76 of fluid delivery assembly 70 and fluid port 54 ofcarrier 30 form a fluid interconnect 80 which fluidically couples fluiddelivery assembly 70 with fluid manifold 52 of carrier 30. As such,fluid outlet 76 constitutes a fluid coupling associated with fluiddelivery assembly 70 and fluid port 54 constitutes a fluid couplingassociated with carrier 30. Thus, the fluid coupling of fluid deliveryassembly 70 mates with the fluid coupling of carrier 30 to deliver fluidfrom fluid delivery assembly 70 to carrier 30. Accordingly, a singlefluid connection is established between fluid delivery assembly 70 andcarrier 30 with fluid interconnect 80.

In one embodiment, as illustrated schematically in FIG. 10, fluiddelivery assembly 70 includes a pressure regulator 90 and a filter 100.Pressure regulator 90 and filter 100 are contained within a chamber 78of housing 72. In one embodiment, pressure regulator 90 receives fluidfrom fluid inlet 74 and regulates a pressure of the fluid for deliveryto carrier 30 and printhead dies 40. In addition, filter 100 receivespressure regulated fluid and filters the fluid before delivery tocarrier 30 and printhead dies 40. In one embodiment, fluid from filter100 is supplied to fluid manifold 52 of carrier 30 via fluid outlet 76of fluid delivery assembly 70 and fluid port 54 of carrier 30.

While fluid manifold 52 of carrier 30 is illustrated as including onefluid chamber, it is understood that fluid manifold 52 may includemultiple fluid chambers. Carrier 30 including multiple fluid chambers isdescribed, for example, in U.S. patent application Ser. No. 10/283,836and U.S. patent application Ser. No. 10/283,860, both assigned to theassignee of the present invention, and incorporated herein by reference.As such, fluid delivery assembly 70 may include fluid inlet 74, fluidinterconnect 80, pressure regulator 90, and filter 100 for each fluidchamber.

FIG. 11 illustrates one embodiment of filter 100. Filter 100 includes aframe 110 having an opening 112 formed therein, fluid fittings 120 and130 associated with frame 110, and filter material 140 enclosing opening112 of frame 110. In one embodiment, frame 110 has a fluid passage 114formed therein which communicates with opening 112. As such, filtermaterial 140 also encloses fluid passage 114 of frame 110. In addition,fluid fittings 120 and 130 are associated with frame 110 so as tocommunicate with fluid passage 114, as described below.

In one embodiment, fluid fittings 120 and 130 each include a respectivefluid port 122 and 132, and a respective fluid passage 124 and 134communicated with the respective fluid port 122 and 132. Fluid fittings120 and 130 are associated with frame 110 such that fluid passages 124and 134 of fluid fittings 120 and 130 communicate with fluid passage 114of frame 110. As such, fluid passages 124 and 134 of fluid fittings 120and 130 communicate with opening 112 of frame 110 via fluid passage 114of frame 110.

In one embodiment, frame 110 has a first face 116 and a second face 117.Second face 117 is opposite of first face 116 and, in one embodiment,oriented substantially parallel with first face 116. In one embodiment,opening 112 communicates with first face 116 and second face 117. Assuch, filter material 140 is provided on first face 116 and second face117 of frame 110.

In one embodiment, filter material 140 is secured to first face 116 andsecond face 117 of frame 110 around a perimeter of opening 112. Inaddition, frame 110 includes one or more separators 119 which extendwithin opening 112 between opposite sides of opening 112. As such,separators 119 prevent filter material 140 provided on first face 116and second face 117 of frame 110 from contacting within opening 112.

In one embodiment, as illustrated in FIG. 11, frame 110 has asubstantially rectangular shape. In addition, opening 112 has asubstantially rectangular shape. As such, filter material 140 is securedto frame 110 around a perimeter of the substantially rectangular shapeof opening 112. In addition, separators 119 extend within opening 112between opposite sides of the substantially rectangular shape of frame110.

As illustrated in the embodiment of FIG. 11, fluid fittings 120 and 130are spaced from each other and extend from one side of frame 110. In oneembodiment, fluid port 122 of fluid fitting 120 communicates with asupply of fluid within fluid delivery assembly 70 (FIG. 10) and fluidport 132 of fluid fitting 130 communicates with fluid manifold 52 ofcarrier 30 (FIG. 10).

In one embodiment, as described below, air passes through filtermaterial 140 before filter material 140 is wetted by liquid ink and airis prevented from passing through filter material 140 when filtermaterial 140 is wetted by liquid ink. In one embodiment, filter material140 includes, for example, a mesh material having a mesh size whichprevents air from passing therethrough when the mesh material is wettedby liquid ink. More specifically, while liquid ink may pass through theopenings of the mesh material, under normal operating pressures, airbubbles will not pass through the openings of the mesh material when themesh material is wetted by the liquid ink. In one embodiment, forexample, filter material 140 has a mesh size in a range of approximately2 microns to approximately 20 microns.

In one embodiment, a permeable material 150 is communicated with fluidport 122 of fluid fitting 120. As such, fluid that passes through fluidport 122 of fluid fitting 120 passes through permeable material 150. Inone embodiment, as described below, before permeable material 150 iswetted by liquid ink, permeable material allows air to pass throughfluid port 122. However, when permeable material is wetted by liquidink, permeable material 150 prevents air from passing through fluid port122.

In one embodiment, as illustrated in FIG. 11, permeable material 150includes a porous plug 152. In one embodiment, porous plug 152 is fittedwithin fluid port 122 of fluid fitting 120 such that fluid that passesthrough fluid port 122 passes through porous plug 152. In oneembodiment, porous plug 152 is impregnated with a clogging agent whichcoagulates when wetted by a liquid. As such, air is prevented frompassing through porous plug 152 when porous plug 152 is wetted by liquidink. Material suitable for porous plug 152 is available, for example,from Porex Corporation of Fairburn, Ga.

In another embodiment, as illustrated in FIG. 12, permeable material 150includes a mesh material 154. In one embodiment, mesh material 154 isfit over fluid port 122 of fluid fitting 120 such that fluid that passesthrough fluid port 122 passes through mesh material 154. In oneembodiment, mesh material 154 is selected so as to have a mesh sizewhich prevents air from passing therethrough when mesh material 154 iswetted by liquid ink. More specifically, while liquid ink may passthrough the openings of mesh material 154, under normal operatingpressures, air bubbles will not pass through the openings of meshmaterial 154 when mesh material 154 is wetted by the liquid ink.

In one embodiment, for example, mesh material 154 has a mesh size in arange of approximately 2 microns to approximately 20 microns. Inaddition, in one embodiment, the mesh size of mesh material 154 isselected such that the pressure drop through mesh material 154 is lessthan the pressure drop through filter material 140. In one exemplaryembodiment, mesh material 154 has a mesh size of approximately 7 micronsand filter material 140 has a mesh size of approximately 12 microns. Assuch, the pressure drop through mesh material 154 is less than thepressure drop through filter material 140.

FIGS. 13A and 13B illustrate one embodiment of filling printheadassembly 12 including, more specifically, chamber 78 of fluid deliveryassembly 70 with liquid ink 11. In one embodiment, during filling ofprinthead assembly 12 with liquid ink 11, printhead assembly 12 isoriented such that carrier 30 and printhead dies 40 are above fluiddelivery assembly 70. While chamber 78 of fluid delivery assembly 70 isbeing filled with liquid ink 11, air within chamber 78 is vented (asidentified by dashed arrows 108) through fluid passage 134 and fluidport 132 of fluid fitting 130 to fluid manifold 52 of carrier 30 throughfluid port 54 and escapes through fluid passages 323 of substrate 32 andnozzles 13 (FIG. 7) of printhead dies 40.

Before filter material 140 of filter 100 is wetted by liquid ink 11, airpasses through filter material 140 into opening 112 and into fluidpassage 114 of frame 110. As such, air is vented through fluid fitting130, as described above. However, as filter material 140 is wetted byliquid ink 11, air is prevented from passing through the wetted filtermaterial 140. In addition, in one embodiment, as filter material 140 iswetted by liquid ink 11, capillary action of filter material 140 causesliquid ink 11 to wick up filter material 140 and wet filter material 140to a level higher than the actual level of liquid ink 11 within chamber78 of fluid delivery assembly 70. Thus, as liquid ink 11 within fluiddelivery assembly 70 reaches the level illustrated in FIGS. 13A and 13B,air within fluid delivery assembly 70 can only pass (as identified bydashed arrows 108) through fluid port 122, including through permeablematerial 150, and fluid passage 124 of fluid fitting 120 to fluidpassage 114 of frame 110. As such, air passes through fluid passage 114of frame 110 and escapes through fluid passage 134 and fluid port 132 offluid fitting 130 to fluid manifold 52 of carrier 30, as describedabove.

As the level of liquid ink 11 within fluid delivery assembly 70 exceedsthe level illustrated in FIGS. 13A and 13B, permeable material 150associated with fluid port 122 (including, for example, porous plug 152or mesh material 154) is wetted by liquid ink 11. As such, air isprevented from passing through permeable material 150. In addition,foreign particles within chamber 78 of fluid delivery assembly 70 areprevented, by permeable material 150, from passing through fluid fitting120 into filter 100 and into fluid manifold 52 of carrier 30.

As illustrated in the embodiment of FIG. 14, during operation ofprinthead assembly 12, printhead assembly 12 is oriented such thatcarrier 30 and printhead dies 40 are below fluid delivery assembly 70.As such, a fluid delivery path (as identified by solid arrows 160) isdefined through filter 100 including through filter material 140,through opening 112 and fluid passage 114 of frame 110, through fluidpassage 134 and fluid port 132 of fluid fitting 130, through fluid port54 of carrier 30, and into fluid manifold 52 of carrier 30. As such,fluid fitting 130 of filter 100 constitutes fluid outlet 76 of fluiddelivery assembly 70 (FIG. 10). Thus, printhead dies 40 are suppliedwith liquid ink 11 through fluid passages 323 (FIG. 7), as describedabove.

In one embodiment, as illustrated in FIG. 14, air within fluid manifold52 of carrier 30 and fluid delivery path 160 is collected within filter100. More specifically, as the level of liquid ink 11 falls below thelevel illustrated in FIG. 14, air within fluid manifold 52 passes (asidentified by dashed arrows 109) through fluid port 54 of carrier 30,through fluid port 132 and fluid passage 134 of fluid fitting 130, andthrough fluid passage 114 and into opening 112 of frame 110 of filter100. Since filter material 140 is wetted by liquid ink 11, air isprevented from passing through filter material 140 to chamber 78 offluid delivery assembly 70. As such, air is trapped within filter 100.Thus, operating pressure of printhead assembly 12 is more readilyregulated by pressure regulator 90 (FIG. 10) since the addition of airto chamber 78 of fluid delivery assembly 70 is minimized.

As illustrated in the embodiments of FIGS. 14 and 15, fluid port 132 hasa longitudinal axis 133 and frame 110 is oriented substantially parallelwith longitudinal axis 133. In addition, fluid port 132 of fluid fitting130 is offset from frame 110 of filter 100. More specifically, fluidport 132 is offset from frame 110 in a direction substantiallyperpendicular to longitudinal axis 133 of fluid port 132. In oneembodiment, fluid fitting 130 extends from second face 117 of frame 110such that fluid passage 134 of fluid fitting 130 extends between fluidport 132 of fluid fitting 130 and fluid passage 114 of frame 110. Assuch, fluid passage 134 of fluid fitting 130 extends generallyperpendicular to longitudinal axis 133 of fluid port 132.

As illustrated in the embodiments of FIGS. 14 and 15, fluid passage 134of fluid fitting 130 has a surface 136 oriented at an angle tolongitudinal axis 133 of fluid port 132. In one embodiment, asillustrated in FIG. 14, the angle of surface 136 is approximately aright angle. In another embodiment, as illustrated in FIG. 15, the angleof surface 136 is an acute angle. In one embodiment, for example, theangle of surface 136 is approximately 30 degrees.

As illustrated in the embodiments of FIGS. 16A and 16B, by orientingsurface 136 of fluid passage 134 at an acute angle relative to thelongitudinal axis of fluid port 132, surface 136 of fluid passage 134becomes a sloped surface. As such, fluid passage 134 can direct air fromfluid port 132 to fluid passage 114 and, therefore, opening 112 of frame110 when printhead assembly 12 is oriented at an angle relative to avertical axis or orientation. Printhead assembly 12 may be oriented atan angle relative to a vertical axis or orientation, for example, whenarranged around a cylindrical paper guide.

For example, as illustrated in the embodiment of FIG. 16A, whenprinthead assembly 12 is oriented at a negative angle relative to avertical orientation, surface 136 of fluid passage 134 can direct airfrom fluid port 132 to opening 112 of frame 110 without creating an areawhere air may become trapped in fluid passage 134 as air is vented fromfluid manifold 52 and through fluid fitting 130 to opening 112 of frame110. In addition, as illustrated in the embodiment of FIG. 16B, whenprinthead assembly 12 is oriented at a positive angle relative to avertical orientation, surface 136 of fluid passage 134 can direct airfrom fluid port 132 to opening 112 of frame 110 without creating an areawhere air may become trapped in fluid passage 134 as air is vented fromfluid manifold 52 and through fluid fitting 130 to opening 112 of frame110.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. This application isintended to cover any adaptations or variations of the specificembodiments discussed herein. Therefore, it is intended that thisinvention be limited only by the claims and the equivalents thereof.

1-32. (canceled)
 33. A method of supplying liquid ink to a printheadassembly including a carrier, a printhead die mounted on the carrier,and a fluid delivery assembly communicated with the carrier, the methodcomprising: communicating a fluid manifold of the carrier with theprinthead die; communicating the fluid delivery assembly with the fluidmanifold of the carrier; and filling the fluid delivery assembly with aquantity of the liquid ink, including purging air from the fluiddelivery assembly through a filter, wherein the filter includes a framehaving an opening and a fluid passage communicated with the openingformed therein, filter material enclosing the opening and the fluidpassage of the frame, first and second fluid ports communicated with thefluid passage, and a permeable material communicated with the firstfluid port.
 34. The method of claim 33, wherein purging air from thefluid delivery assembly includes directing air from the first fluid portto the second fluid port through the fluid passage of the frame.
 35. Themethod of claim 33, wherein purging air from the fluid delivery assemblyincludes passing air through the permeable material before the permeablematerial is wetted by liquid ink and preventing air from passing throughthe permeable material when the permeable material is wetted by theliquid ink.
 36. The method of claim 33, wherein the permeable materialof the filter includes a porous plug fitted within the first fluid port.37. The method of claim 36, wherein the porous plug is impregnated witha clogging agent.
 38. The method of claim 33, wherein the permeablematerial of the filter includes a mesh material.
 39. The method of claim33, wherein filling the fluid delivery system with the liquid inkincludes passing the liquid ink through the filter material andpreventing air from passing through the filter material when the filtermaterial is wetted by the liquid ink.
 40. The method of claim 39,wherein purging air from the fluid delivery assembly includes passingair through the filter material before the filter material is wetted bythe liquid ink.
 41. A method of supplying liquid ink to a printhead diemounted on a carrier, the method comprising: communicating a fluidmanifold of the carrier with the printhead die; communicating a fluiddelivery assembly with the fluid manifold of the carrier, the fluiddelivery assembly containing a supply of the liquid ink; anddistributing the liquid ink to the printhead die through the fluiddelivery assembly and the fluid manifold, including routing the liquidink through a filter of the fluid delivery assembly, wherein the filterincludes a frame having an opening and a fluid passage communicated withthe opening formed therein, filter material enclosing the opening andthe fluid passage of the frame, first and second fluid portscommunicated with the fluid passage of the frame, and a permeablematerial provided in a fluid path of the first fluid port.
 42. Themethod of claim 41, wherein routing the liquid ink through the filterincludes passing the liquid ink through the filter material andpreventing air from passing through the filter material when the filtermaterial is wetted by the liquid ink.
 43. The method of claim 41,wherein routing the liquid ink through the filter includes passing theliquid ink through the filter material and into the opening and thefluid passage of the frame and through the second fluid port to thefluid manifold of the carrier.
 44. The method of claim 41, furthercomprising: collecting air from the fluid manifold of the carrier in thefilter, including directing the air from the second fluid port throughthe fluid passage to the opening of the frame and trapping the airwithin the opening with the filter material.
 45. The method of claim 44,wherein directing the air includes directing the air from the secondfluid port through the fluid passage to the opening of the frame whenthe printhead assembly is oriented at an angle.
 46. The method of claim41, wherein the second fluid port of the filter has a longitudinal axis,and wherein the frame of the filter is oriented substantially parallelwith the longitudinal axis of the second fluid port.
 47. The method ofclaim 46, wherein a fluid passage of the second fluid port has a surfaceoriented at an angle to the longitudinal axis of the second fluid port.48. A method of supplying liquid ink to a printhead assembly including acarrier, a printhead die mounted on the carrier, and a fluid deliveryassembly communicated with the carrier, the method comprising:communicating a fluid manifold of the carrier with the printhead die;communicating the fluid delivery assembly with the fluid manifold of thecarrier; and filling the fluid delivery assembly with a quantity of theliquid ink and distributing the liquid ink to the printhead die throughthe fluid manifold, including routing the liquid ink through a filter ofthe fluid delivery assembly and purging air from the fluid deliveryassembly through the filter, wherein the filter includes a frame havingan opening and a fluid passage communicated with the opening formedtherein, filter material enclosing the opening and the fluid passage ofthe frame, first and second fluid ports communicated with the fluidpassage, and a permeable material provided in a fluid path of the firstfluid port.
 49. The method of claim 48, wherein routing the liquid inkthrough the filter includes passing the liquid ink through the filtermaterial and preventing air from passing through the filter materialwhen the filter material is wetted by the liquid ink.
 50. The method ofclaim 48, wherein routing the liquid ink through the filter includespassing the liquid ink through the filter material and into the openingand the fluid passage of the frame and through the second fluid port tothe fluid manifold of the carrier.
 51. The method of claim 48, whereinpurging air from the fluid delivery assembly includes directing air fromthe first fluid port to the second fluid port through the fluid passageof the frame.
 52. The method of claim 48, wherein purging air from thefluid delivery assembly includes passing air through the permeablematerial before the permeable material is wetted by the liquid ink andpreventing air from passing through the permeable material when thepermeable material is wetted by the liquid ink.